What are the 3 fibers in the cytoskeleton?

Microtubules, Intermediate Filaments, and microfilaments

Rank the fibers in size from smallest to largest

Smallest: microfilaments medium: intermediate filaments largest: microtubules

What are microtubules made up of?

tubulin which forms hollow rods

Where do the microtubules grow out of?

centrosomes

What is the purpose of microtubules?

1. shape and support cell 2. serves as tracks for motor proteins 3. involved in separation of chromosomes 4. form cilia and flagella

What are cilia?

microtubule extensions that move fluid over the surface of tissue and act as a receiving antenna crucial for brain function

What are flagella?

microtubule extensions that act to move the cell in water

What are intermediate filaments made up out of?

many different proteins, keratin

Where are intermediate filaments found?

only found in SOME animal cells

What is special about intermediate filaments?

They are more permanent and sturdier than the other fibers

What is the purpose of intermediate filaments?

1. bearing tension 2. reinforcing shape 3. fixing position of organelles

What organelle component does intermediate filaments help make up?

the nuclear lamina

What are microfilaments made up out of?

Actin; twisted double chain of actin subunits

What is the purpose of microfilaments?

1. Bear tension 2. structural network 3. support shape 4. cell motility

what causes muscle contractions?

actin and myosin

what processes are microfilaments involved in?

amoeboid crawling and cytoplasmic streaming